Normalise indentation
A mnemonic is probably more readable here

It's a one-liner and there's only one block variable.
Gather class variables in one place
Build a person hierarchy for breadcrumbs

A person can have more than one hierarchy, so we use a hint to decide
which one if there's ambiguity.
Show breadcrumbs for people

Where there are multiple possible breadcrumb trails for a person, choose
the one that matches the last group visited.